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Abstract: Background: In the current study, as a first step to develop a monitoring method of cerebellar functions, we tried to record evoked potentials on the cerebellar cortex by electrical stimulation of the rat SCT, which is located in the Inf-CPed. Methods: The experimental study was performed on rats. Unilateral muscular contractions of quadriceps femoris muscle were elicited by electrical stimulation. The evoked potentials were recorded from the surface of the ipsilateral cerebellum and the contralateral primary sensory cortex. Results: The highly reproducible potentials obtained from the ipsilateral cerebellar hemisphere were named SCEP. The SCEP exhibited one negative peak with a latency of 11.7 ± 0.3 milliseconds (N11). Short-latency somatosensory evoked potential was recorded from the contralateral primary sensory cortex with a latency of 19.1 ± 0.6 milliseconds. Coagulation of the ipsilateral Inf-CPed caused disappearance or marked reduction of the SCEP N11, but it did not change the SSEP. On the other hand, sectioning of the ipsilateral dorsal column resulted in the disappearance of the SSEP, but it did not affect the SCEP N11. Conclusions: Reproducible SCEP was recorded from the rat cerebellar hemisphere by electrical stimulation of the quadriceps femoris muscle. We posit that the SCEP differs from the SSEP, which ascends via the dorsal column, and that it is conducted by the dorsal SCT located in the Inf-CPed. Our results suggest that it may be possible to detect the dysfunction of the Inf-CPed electrophysiologically by using SCEP. [Copyright &y& Elsevier]

Abstract: The paths of embryonic chick spinal commissural neurons originating from the lumbosacral (LS) 2 spinal segment and born around Hamburger-Hamilton stage (HH) 18 were observed by labeling the axons with an in ovo electroporation method designed to limit the electroporated area to ~one somite length. After crossing the floor plate, these axons followed two major paths, one ventral and one dorsal, and a minor path running between the major ones. These axons reached the brachial region by HH28, passed through the cervical region at HH29, and entered the medullary area by HH30. The dorsal axons entered the developing cerebellum by HH33, crossed the midline again, and spread into the rostral–ipsilateral area of the developing cerebellum so that most of them were confined to lobules II–III by HH39. A small population of ventrally running axons turned to enter the cerebellum, and the rest entered the superior medullary velum between the cerebellum and the midbrain. The LS2-originating axons that ascended ipsilaterally into the cerebellum followed a single path, and their extension was delayed compared with that of the commissural axons. Some of the ipsilateral axons innervated the cerebellum; the rest entered the superior medullary velum. These direct observations of the formation of part of the spinocerebellar projections in chick will be a useful reference for future analyses of the underlying mechanisms. [Copyright &y& Elsevier]

Abstract: We describe a 39-year-old Japanese woman with familial amyotrophic lateral sclerosis (FALS) in whom we identified a missense mutation (Gly93→Ser) in exon 4 of the Cu/Zn superoxidase dismutase-1 (SOD1) gene in which no pathological data have been available. The disease duration was 16 years, and she died of respiratory failure. The initial sign was weakness of the lower limbs. She had no clear upper motor neuron involvement. Respiratory muscle weakness had developed 1 year before her death. Neuropathological examinations showed simultaneous involvement of the pyramidal tract and lower motor neurons as well as degeneration in the Clarke''s nucleus, the spinocerebellar tract, the posterior column, the dentatorubral system, and anterolateral columns of the spinal cord. However, the patient has no Lewy body-like hyaline inclusions (LBHIs), which are characteristic features of mutant SOD1-related FALS with posterior column involvement. Based on clinical, genetic and pathological findings with a review of the literature, we suggest that degeneration of the dentatorubral system and the absence of LBHIs in our case are pathological features in FALS with the Gly93Ser mutation. [Copyright &y& Elsevier]

We examined the characteristic clinical features of one family of familial amyotrophic lateral sclerosis (FALS) with a His46Arg mutation in the enzyme Cu/Zn superoxide dismutase-1 (SOD1). The disease duration for this family was 18.1±13.2 (mean±S.D.) years, with the age at onset being 39.7±10.5 years old (mean±S.D.). The initial sign was distal weakness of the unilateral lower limb, extending to the lower limb of the other side. A wheel chair became necessary at 9.8±3.2 years after the onset. Upper limb weakness started at 15.5±8.9 years following from the onset. An autopsy was performed on a 71-year-old woman of the family with the mutation. Her disease duration was 47 years, and she died of pneumonia. She had no clear upper motor neuron involvement. Bulbar sign and respiratory muscle weakness had developed 2 years before her death. Neuropathological findings showed degeneration of corticospinal tracts, anterior/posterior spinocerebellar tracts, posterior columns, and Clarke''s columns. There were few anterior horn cells in the lumbar spinal cord and no Lewy body-like hyaline inclusion bodies in these remaining anterior horn neurons. This is the first autopsy report of FALS with a His46Arg mutation in the SOD1 enzyme. [Copyright &y& Elsevier]

• Cervical, brachial, thoracic, and lumbar ascending tract formation are visualized. • The ascending tracts originating in different spinal segments develop similar paths. • However, their elongation and cerebellar projection profiles are different. The present study aimed to assess spinal tract formation in neurons originating from cervical (C7), brachial (C14), and thoracic (T4) regions, with the lumbar (LS2) region as a reference, in a chick embryo. For the assessment of the spinal tracts, we introduced a vector expressing human placental alkaline phosphatase into progenitor cells generated after neural tube closure and belonging to the above segments, using in ovo electroporation. The ascending axons took primarily similar paths: dorsal commissural, ventral commissural, and dorsal non-commissural paths, with some variance depending on their originating segments. Some populations of non-commissural neurons later extended their axons following a ventral path. The elongation rates of these axons are primarily constant and tended to increase over time; however, some variations depending on the originating segments were also observed. Some of the dorsally ascending axons entered into the developing cerebellum, and spinocerebellar neurons originating from T4 projected their axons into the cortex of the cerebellum differently from those from LS2. These results unveil an overall picture of early ascending spinal tract formation. [ABSTRACT FROM AUTHOR]